1. Technical Field
The present invention relates to a device with an antenna function, and relates more particularly to an electronic device that is primarily worn by a person or animal when used.
2. Related Art
Japanese Unexamined Patent Appl. Pub. JP-A-H10-197662 discloses a mobile receiver device as an example of an electronic device that has an internal antenna and is used worn on the arm. This mobile receiver device has a circuit board with a sandwich structure having an electromagnetic shield layer inserted between the front and back sides of the circuit board, a digital circuit unit and a reception antenna disposed on one side of the circuit board as part of a receiver circuit, and an analog circuit unit forming another part of the receiver circuit disposed on the other side of the circuit board opposite the reception antenna with the circuit therebetween. The analog circuit unit that is easily affected by noise is electromagnetically shielded from the digital circuit unit that is a source of high frequency digital noise by the electromagnetic shield layer embedded in the circuit board in this mobile receiver device, and leakage or mixing of noise from the digital circuit unit to the analog circuit unit is effectively suppressed by this electromagnetic shielding. The digital circuit unit and analog circuit unit can therefore be disposed close together in this mobile receiver device to increase the packaging density and reduce device size while reception performance is also improved by reducing or eliminating the effect of noise.
However, while the technology of the related art enables suppressing the effect of the digital circuit unit and making the mobile receiver device small, further reducing the size using the general configuration taught in JP-A-H10-197662, and more specifically a configuration that connects an LCD panel or other display unit to the reception antenna side with a flat cable, is impeded by the effect of the LCD panel or flat cable on the reception antenna causing impedance to fluctuate and degrading radiation efficiency.
Another problem with the above technology is that the size of the display unit is limited by the antenna, display unit, and digital circuits being disposed side by side on a flat surface. As a result, a large amount of information cannot be presented on the display unit in an advanced, high performance electronic device, and the design and appearance of the outside case of the electronic device is also severely limited. This is because of technical constraints that require the conventional reception antenna to be disposed near the surface of the outside case in order to receive signals. Yet further, in an electronic device that is worn by a person or animal when used, the transmission and reception performance of the antenna must not vary greatly according to how the device is worn.